Junit tips and tricks

Since I don't know how your factory method looks like, all I can advise right now is to

1. Check to see the object is the correct concrete implementation you were looking for:

   IMyInterface fromFactory = factory.create(...);  
   Assert.assertTrue(fromFactory instanceof MyInterfaceImpl1);

2. You can check if the factory setup the concrete instances with valid instance variables.
3. http://stackoverflow.com/questions/37310/checking-the-results-of-a-factory-in-a-unit-test